Secondary-battery separator.



UNITED STATES PATENT OFFICE.

HUGH RODMAN, OF PITTSBURGH, PI ENNSYLVANIA, ASSIGNOR, BY MESNE ASSIGN-MENTS, TO THE ELECTRIC STORAGE BATTERY COMPANY, OF PHILADELPHIA,PENNSYLVANIA, A CORPORATION OF NEW J'ERSEY.

SECONDARY-BATTERY SEPARATOR.

No Drawing.

To all whom it may concern Be it known that I, HUGH RQDMAN, a dissolvingin water.

citizen. of the United States, and a resident of Pittsburgh, in thecounty of Allegheny and State of Pennsylvania, have made a new anduseful Invention in Secondary- Battery Separators, of which thefollowing is a specification.

I have discovered a material which, I believe, is perfectly satisfactoryfor the manufacture of storage battery separators. The material is aporous glass which is made by putting ground or powdered glass While dryand pulverulent into suitable molds and subjecting the molded mass,while 'still in a pulverulent condition, to a fritting tempera I turefor a suitable length of time.

The method I am now using in carrying out my Invention consists 1nplacing powdered glass, such as is obtained commercially, in an iron orclay mold and subjecting 1t while in the mold and still in a pulverulentcondition to .a temperature of about 1200 or 1250 F. for a periodranging from thirty minutes to an hour. The se arate particles of.glass, of the molded an pulverulent mass, when subjected to thistemperature for a suflicient length of time, frit together and produce astrong and very porous glass ware which is admirably suited for purposesordinarily served by weaker and less porous earthenware. During thefritting operation the separate particles of glass settle somewhat,depending upon the v time and temperature of heating.

I have also successfully molded finely ground glass while it is wet, byusing with it a setting material, such, for instance, as magnesiumsulfate, which, in drying, sets the mass of molded glass so that it maybe subsequently heated to frit the separate particles of glass together.The magneslu'm Specification of Letters Patent.

Patented Jan. 28, 1913.

Application filed March 24, 1908. Serial No. 422,974.

sulfate may subsequently be eliminated by I do not believe, however,that this process produces nearly as good results as the fritting of thedry pulverulent mass. I

Either process produces a porous glass which is far superior, as regardsstrength, inertness. porosity and ability to resist the effects ofchanges of temperature, to any material with which I am familiar.

I believe there is a peculiar merit attached to the method of burningorfiring the molded mass while in a dry, pulverulent condition. ,Justwhat the explanation of this advantage is I am unable to definitelystate, but I believe it is due to the settling which occurs to someextent during the fritt-ing I -Which forms the invention, but I desireto have it understood that other methods may be employed and still fallwithin its spirit;7o

and scope.

, What I a claim is 1. A' porous separator formed of finely- I dividedglass, molded without a binder, and fritted.

2. An electric battery separator consist.- ing of an integral mass ofporous glass.

In testimony whereof, I have hereunto subscribed my name this 21st dayof March, 1908.

I HUGH RODMAN.

Witnesses:

CHARLES W. MCGHEE, E. W. MCCALLISTER.

